Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 84,040	$ 78,591	$ 91,157	$ 88,354	$ 108,066	$ 116,143	$ 107,737	$ 253,788	$ 331,946
Weighted average number of common shares outstanding - basic (in shares)	217,051				218,416			216,955	219,791
Effect of potentially dilutive common shares (in shares)	335				562			398	487
Weighted average number of shares outstanding, diluted (in shares)	217,386				218,978			217,353	220,278
Earnings per common share:
Basic (in dollars per share)	$ 0.39				$ 0.49			$ 1.17	$ 1.51
Diluted (in dollars per share)	$ 0.39				$ 0.49			$ 1.17	$ 1.51